Coupling device for underwater wellheads



Nov. 29, 1966 c. c, BROWN 3,288,493

COUPLING DEVICE FOR UNDERWATER WELLHEADS Filed Feb. 28, 1964 :5 Sheets-$heet 1 n: E Y E f 0 C. OWN

NTO

ATTOR/VEV Nov. 29, 1966 c. c. BROWN 2 COUPLING DEVICE FOR UNDERWATER WELLHEADS Filed Feb. 28, 1964 5 Sheets-Sheet 2 Nov. 29, 1966 c. c. BROWN 3,288,493

COUPLING DEVICE FOR UNDERWATER WELLHEADS Filed Feb. 28, 1964 {5 Sheets-Sheet 5 United States Patent 3,288,493 COUPLING DEVICE FOR UNDERWATER WELLHEADS Cicero C. Brown, Brown Oil Tools, Inc., P.O. Box 19236, Houston, Tex. Filed Feb. 28, 1964, Ser. No. 348,070 6 Claims. (Cl. 285-3) head by means of suitable guidance and connection devices. In particular, it is often necessary to connect a string of well pipe or casing to the wellhead after the latter is in place and it is highly desirable that the operations involved in such connection be effected by only longitudinal movements of the pipe string being lowered into the water body, as rotational movements are likely to prove inconvenient and more diflicult of manipulation than straight vertical movements of the pipe string.

It is a primary object, in accordance with this invention, to provide an improved form of coupling or connecting device by which connection of a pipe string with a submerged wellhead may be effected with a minimum of difliculty and with maximum efficiency.

A further object is to provide a coupling device of the character described which is actuated entirely by longitudinal movements of the pipe to which it is connected.

A further object is the provision of a coupling device of the character described, which is releasable also 'by relative longitudinal movements of its parts.

Other and more specific objects and advantages of this I invention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates two useful embodiments in accordance with this invention.

In the drawing:

FIG. 1 is a longitudinal, quarter-sectional view showing the coupling device with the parts in the positions occupied when being installed in the wellhead;

FIG. 2 is a view similar to FIG. 1 showing the device locked in place in the wellhead;

FIG. 3 is a view similar to FIGS. 1 and 2 showing the parts in releasing position;

FIG. 4 is a cross-sectional view taken along line 44 of FIG 1;

FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 2;

FIG. 6 is a fragmentary, partly sectional view illustrating a modification of the coupling device;

FIG. 7 is a cross-sectional view taken along line 77 of FIG. 6; and

FIG. 8 is a generally diagrammatic view showing the device in position in a submerged wellhead.

Referring to the drawing, there is shown a conventional wellhead H which, it will be understood, is conventionally connected to the upper end of a large diameter conductor pipe (not shown) extending into a well bore drilled into the land bottom B at an undersea location, the wellhead H extending a short distance above the top of the land bottom and provided with an annular flange F at its upper end for connection of superposed wellhead structures.

A coupling device, designated generally by the numeral 10, comprises an outer tubular receptacle or housing 11 threadedly connected at its lower end to a tubular bushing 12 provided with an annular laterally extending flange 13 by which the housing may be connected to flange F by 3,288,493 Patented Nov. 29, 1966 ice means of bolts 14. Bushing 12 has a bore 15 which is substantially flush with the bore of wellhead H. The inner end of bushing 12 is shaped to provide an upwardly projecting annular flange 16 which is radially spaced from the inner wall of housing 10 to define the annular space 17 between flange 16 and the inner wall of housing 11. The upper end of the latter may be provided with the lateral enlargement 18, the upper end of which is provided with a downwardly and inwardly inclined surface 19 which serves as a guide for the tools to be inserted in the bore of housing 11. At an intermediate point along its length the inner wall of housing 11 is provided with an annular groove 20, defined by upper and lower inclined end walls 20a-20a, which serves as the locking or landing recess for the co-operating inner portions of the coupling device. The latter include a tubular body 21 having an external diameter to form a close sliding fit in the bore of housing 1. Body 21 has an internally threaded box 22 at its upper end to receive the threaded pin 23 of a sub 24 which serves to connect the coupling device to a pipe string, such as casing C (FIG. 8), which is to be coupled to a wellhead. Seal packing 25 of any suitable type is seated in the exterior of sub 24 and is adapted to form a fluid-tight seal between the latter and housing 11 when the inner portions of the coupling device are inserted in housing 11. Body 21 is provided at a level below box 22 with a plurality of radial openings 26 of generally rectangular configuration. As best seen in FIGS. 4 and 5, three such openings are pro vided on spacing but a greater number may be provided if desired. A latching dog 27, of the same general configuration as opening 26, is mounted in each of the openings 26 for free radial movement therein into and out of latching engagement with recess 20, as will appear subsequently. The inner face of latching dog 27 is provided with longitudinally spaced, inwardly projecting lugs 27a-27a, the upper and lower edges of which are chamfered. The space between the lugs 27a defines a recess 27b. The opposite side edges of lugs 2711 are formed to provide lateral extensions 27c which extend inside the related edges of openings 26 to prevent outward dislodgment of dogs 27 from the openings. A tubular extension sleeve 28 is threadedly connected to the lower end of body 21 with its exterior flush with that of body 21. Sleeve 28 is provided at its lower end with an inwardlyturned lip defining the upwardly facing annular shoulder 29 for purposes to appear subsequently.

Slidably mounted in the bore of body 21 is a tubular mandrel 30 provided near its upper end with an annular enlargement 31 defining an external shoulder about the mandrel and having its upper and lower edges inclined to complement the inclined surfaces on the spaced-lugs 27a, 27a, and having a length such as to fit snugly in recess 27b. A short distance above its lower end, mandrel 30 is provided with an external downwardly facing shoulder 32 which is longitudinally spaced above shoulder 29 on extension sleeve 28. A coil spring 33 is mounted about the lower end of mandrel 30 in compression between shoulders 29 and 32, so as to resiliently bias mandrel 30 and body 21 in opposite longitudinal directions. Mandrel 30 will be initially held in an inactive or non-actuating position by means of one or more shear pins 34 which extend radially through the walls of body 21 and mandrel 30, as best seen in FIG. 1. In this inactive position of the mandrel, enlargement 31 will be positioned to extend into the space 27b provided between the lugs 27a, 27a and thereby permit inward movement of dogs 27 to a retracted position Within the exterior periphery of body 21. It will be seen that in response to relative longitudinal movement between mandrel 30 and body 21, enlargement 31 will be moved 0pposite upper lug 27a and another shoulder 3111 on mandrel 30 will be opposite lower lug 27a so as to project dogs 27 radially outwardly sufiiciently to be received in latching engagement in groove 20, as best seen in FIG. 2. Upward movement of mandrel 30 relative tobody 21 to the dog-projecting position, will be limited by engagement of the upper end of mandrel 30 with the lower end of pin 23 (FIG. 2).

The lower end of mandrel 30 is dimensioned to be in coaxial alignment with the upper end of flange 16 while the thickness dimension of the lower end of extension sleeve 28 will be made such that it will be aligned with space 17 and will be free to move downwardly into this space in the operation of the device, as will be described hereinafter. In operation, body 21 will be secured to the lower end of sub 24, as illustrated particularly in FIG. 1, and will be lowered from a drilling barge or the like (FIG. 8) on the pipe string C, which is to be coupled to the wellhead, and thereby introduced into the bore of housing 11. As illustrated, the coupling device and the pipe string to which it is connnected will be stripped over smaller diameter pipe P which may already be in place in the well bore and extend through the bore of the wellhead. In any event, as pipe string C carrying the coupling device is inserted in the bore of housing 11 and lowered therein, the lower end of mandrel 30 will strike the upper end of flange 16. Weight may then be applied to the pipe string carrying the coupling device, as by slacking-off on the lowering line, and this weight may be applied to an extent sufiicient to break shear pins 34 (FIG. 2). The breaking of the shear pins will then allow body 21 to move downwardly relative to mandrel 30, this relative downward movement being limited by engagement of the lower end of extension 28 with the upper end of bushing 12 which defines the bottom of space 17. The amount of relative movement thus permitted will be suflicient to cause enlargement 31 on the mandrel to move upwardly behind the upper lug 27a and the shoulder 31a on the mandrel to move behind the lower lug 27a, projecting dogs 27 into locking groove in the outer housing. The upward movement of the mandrel will be limited by engagement of the upper end thereof with the pin 23 so that the latching engagement of the dogs in groove 20 will be maintained, since the mandrel can no longer move in either direction and the weight of the pipe will necessarily hold body 21 in its relative downward position, as limited by the upper end of bushing 12.

If high pressure in the wellhead overcomes the weight of casing C and moves the body 21 upwardly until the dog 27 engages the upper end 20a of groove 20 the mandrel 30 will move off of flange 16. However, the spring 33 will keep the mandrel 30 in its upward position, maintaining the dogs 27 outward in locking position.

Accordingly, it will be seen that coupling of the pipe string to the wellhead has now been effected solely by a simple downward movement applied to the pipe string being coupled to the well-head. With the coupling device in place, seal packaging will prevent leakage of fluid past the coupling device.

Release of the coupling device may be readily effected in order to permit withdrawal of pipe string C from the well-head. For this purpose, mandrel is provided on its inner surface with :an annular recess 36 defined'at its lower end by an upwardly facing annular shoulder 37. To effect release, a releasing tool 38 of a generally conventional design, mounted on an operating pipe string P, will be run through the bore of easing C into the bore of mandrel 30. Releasing tool 38 will be provided with outwardly biased spring-actuated dogs 39 which will engage shoulder 37 when the tool is lowered to a point opposite recess 36 and upon application of downward force to operating string P downward pressure will be exerted against the mandrel. At the same time, an upward pull may be applied to casing C so as to pull body 21 upwardly relative to mandrel 30, which, as noted, will be held in its lowermost position by means of the releasing tool. This relative upward movement of housing 21 will move latching dogs 27 upwardly relative to enlargement 31 on the mandrel until the latter is opposite recess 27b. This will allow the latching dogs to retract under the force of the upward pull which will be effective, through engagement of the bevelled upper ends of the latching dogs with the bevelled upper wall 20a of groove 20, to push the latching dogs inwardly to their retracted position and allow the coupling device to then be pulled out of housing 11 for removal from the wellhead.

It will be evident here also that the releasing operations require only vertical movements of the tool string carrying the releasing device 38 and of casing C.

FIGS. 6 and 7 illustrate a modification of the coupling device employing a somewhat different arrangement of the biasing springs between body 21 and mandrel 30. In the modification, the single coil spring 33 is replaced by a plurality of smaller coil springs 133 mounted in compression between upper and lower end rings 40 and 41, respectively, slidably disposed in the annular space between extension sleeve 28 and the lower end portion of mandrel 30 which extends below shoulder 32. The latter and a shoulder 42 on extension 28 hold the rings in place. The ends of the coil springs 133 are seated in registering sockets 44 in the opposed faces of rings 40 and 41. Guide pins 45 are secured at their upper ends to upper ring 40 and extend through the several coil springs 133 and thence slidably through registering openings 46 in lower ring 41. A sufiicient amount of clearance is provided between the upper end of end ring 40 and the lower end of body 21 to permit the requisite relative longitudinal movement between body 21 and mandrel 30 to perform the latching and releasing manipulations which are the same as previously described.

It will be understood that other changes and modifications may be made in the details of the illustrative embodiments within the scope of the appended claims but without departing from the spirit of this invention.

What I claim and desire to secure by Letters Patent 15:

1. A coupling device for underwater wellheads, comprising, a tubular housing attachable to a submerged wellhead and having an annular locking groove in the bore wall thereof, a tubular connector body coaxially insertable in the bore of said housing, said connector body having a plurality of circumferentially spaced openings through the wall thereof, latching dogs mounted in said openings for radial movement into and out of locking engagement with said groove, seal means mounted about said body above said openings for sealing engagement with said housing, a tubular mandrel slidably disposed for relative axial movement in the bore of said body, an annular enlargement about said mandrel movable therewith between a first position urging said latch- .ing dogs into said groove and a second position releasing said latching dogs for retraction from said groove, abutment means mounted in the bore of said housing in registration with the lower end of said mandrel to limit downward movement of the mandrel relative to said body, resilient means positioned between said mandrel and said body to bias said mandrel toward said first position, holding means initially securing said mandrel to said body in said second position, said holding means being releasable in response to downward force applied to said body after engagement of the lower end of said mandrel with said abutment means, and means for connecting the upper end of said body to a pipe or the like to be coupled to said wellhead.

2. A coupling device according to claim 1, wherein each of said latching dogs has a pair of inwardly extending longitudinally spaced lugs formed thereon defining a recess therebetween adapted to receive said annular enlargement when said mandrel is in said second position.

3. A coupling device according to claim 1, wherein said abutment means comprises an annular upstanding flange radially spaced inwardly from the inner wall of said body.

4. A coupling device according to claim 1, wherein said resilient means comprises a coil spring concentrical- 1y disposed between the lower portions of said mandrel and said body and mounted in compression between opposed longitudinally spaced shoulders on said mandrel and said body.

5. A coupling device according to claim 1, wherein said resilient means comprises a plurality of coil springs References Cited by the Examiner UNITED STATES PATENTS 3,037,797 6/1962 Brown 28518 3,086,590 4/ 1963 Jackson et al.

3,130,788 4/ 1964 Cochran et al.

3,136,366 6/1964 Brown et al. 285-308 X CARL W. TOMLIN, Primary Examiner.

T. A. LISLE, Assistant Examiner. 

1. A COUPLING DEVICE FOR UNDERWATER WELLHEADS, COMPRISING, A TUBULAR HOUSING ATTACHABLE TO A SUBMERGED WELLHEAD AND HAVING AN ANNULAR LOCKING GROOVE IN THE BORE WALL THEREOF, A TUBULAR CONNECTOR BODY COAXIALLY INSERTABLE IN THE BORE OF SAID HOUSING, SAID CONNECTOR BODY HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED OPENINGS THROUGH THE WALL THEREOF, LATCHING DOGS MOUNTED IN SAID OPENINGS FOR RADIAL MOVEMENT INTO AND OUT OF LOCKING ENGAGEMENT WITH THE SAID GROOVE, SEAL MEANS MOUNTED ABOUT SAID BODY ABOVE SAID OPENINGS FOR SEALING ENGAGEMENT WITH SAID HOUSING, A TUBULAR MANDREL SLIDABLY DISPOSED FOR RELATIVE AXIAL MOVEMENT IN THE BORE OF SAID BODY, AN ANNULAR ENLARGEMENT ABOUT SAID MANDREL MOVABLE THEREWITH BETWEEN A FIRST POSITION URGING SAID LATCHING DOGS INTO SAID GROOVE AND A SECOND POSITION RELEASING SAID LATCHING DOGS FOR RETRACTION FROM SAID GROOVE, ABUTMENT MEANS MOUNTED IN THE BORE OF SAID HOUSING IN REGISTRATION WITH THE LOWER END OF SAID MANDREL TO LIMIT DOWNWARD MOVEMENT OF THE MANDREL RELATIVE TO SAID BODY, RESILIENT MEANS POSITIONED BETWEEN SAID MANDREL AND SAID BODY TO BIAS SAID MANDREL TOWARD SAID FIRST POSITION, HOLDING MEANS INITIALLY SECURING SAID MANDREL TO SAID BODY IN SAID SECOND POSITION, SAID HOLDING MEANS BEING RELEASABLE IN RESPONSE TO DOWNWARD FORCE APPLIED TO SAID BODY AFTER ENGAGEMENT TO THE LOWER END OF SAID MANDREL WITH SAID ABUTMENT MEANS, AND MEANS FOR CONNECTING THE UPPER END OF SAID BODY TO A PIPE OR THE LIKE TO BE COUPLED TO SAID WELLHEAD. 